There are no rules, except those that you impose on the situation. And to impose rules you have to espouse them.
You think that you and he were dating. he might have thought that you and he were hanging out. You might have thought your were lovers. he might have thought that you were friends with benefits. (Assuming anytyhing of that nature has been happening. You didn't say, and I'm not certain I should make that assumption.)
Some fellows are never exclusive and will tell you so. Some will say they are exclusive and then cheat. Others will actually be exclusive.
In your case, he has decided that you and he are not going to work. He's cancelled a date. He's revised his POF profile. He's looking. The only thing he didn't do was say it out loud.
What should you do? Accept the situation. If he calls again ask him outright what he thinks is going on and what the rules are. If you can accept them, then go for it. On the other hand, a failing relationship (and this appears to be one) can rarely be revived. For expert advice meet your
Best Friend